Breast cancer remains a leading cause of cancer deaths among women worldwide. Recurrence of cancer is 10-20% within 10 years after surgery and up to 60% or higher in patients with more aggressive cancers. Determining the best adjuvant therapy for an individual is daunting, complex, and often overwhelming, yet is of primary importance for shared decision making between patients and clinicians. To address this need, we will develop and test the feasibility of decide, a mobile decision support tool used in conjunction with adjuvant (postoperative) therapy decisions for breast cancer. decide will (1) use easy to understand multimedia to explain and quantify individualized probabilities of recurrence, mortality, and potential side effects of adjuvant therapies; (2) integrate newer molecular tests (e.g., Oncotype DX and MammaPrint) to refine risks of recurrence and benefit of chemotherapy and hormonal approaches; (3) allow patients to enter, upload, and share key health records (e.g., critical components of medical history, pathology reports and diagnostic imaging records) to facilitate second opinions; and (4) provide video vignettes conveying breast cancer survivors' experiences related to adjuvant therapy. Decide will be a valuable supplemental resource for patients and clinicians to weigh the individualized risks and benefits of adjuvant therapy and facilitate shared decision making. More informed decision making can lead to improved post-decision satisfaction and result in enhanced adherence and more efficient utilization of medical resources. Eyes of the World Media Group (EOW) will execute the project in collaboration with USC Norris Comprehensive Cancer Center. EOW has a successful track record producing health-centered mobile and web resources in partnership with research institutions. USC Norris is a major regional and national resource for cancer research, treatment, prevention, and education, and is designated by the National Cancer Institute as one of the nation's 40 comprehensive cancer centers. In this Phase I proposal, EOW aims to 1) conduct formative research through an online needs assessment with patients and providers to inform the development of the product; 2) develop a working prototype that contains decision support software, chemotherapy related info graphics, and a 1-3 minute video vignette; and 3) conduct a feasibility study. Qualitative and quantitative methods will assess the satisfaction, usefulness, comprehensibility, and usability of such a mobile resource for shared decision making. The mixed methodology approach of this Phase I effort will provide rich, sound data that will inform development of the full featured mobile resource in Phase II. We hypothesize decide may prove a valuable resource for patients and clinicians in making personalized, informed, and evidence-based decisions related to adjuvant therapy for breast cancer. ! PUBLIC HEALTH RELEVANCE: This mobile decision support resource is intended to facilitate shared decision making for complex treatment decisions after breast cancer surgery. It will help patients better understand individualized probabilities of expected benefits and risks of adjuvant therapy facilitate communication, and integrate portable electronic health records for second opinions. Ultimately, more informed decisions on adjuvant therapy can lead to better decision satisfaction, which may improve resource utilization, treatment adherence, and long-term survival for breast cancer patients.